A wireless system has the function of performing adaptable configuration of a link rate according to the status (for example, a received signal strength indication or communication quality) of a link between an access point (hereinafter referred to as an AP) and a station (hereinafter referred to as an STA). In particular, in the wireless system, such as a wireless LAN, which adopts a link adaptation method, a modulation method according to the status of a link is selected, whereby it is possible to set a corresponding link rate.
Incidentally, as for an application used under such circumstances, a previously set application is booted irrespective of link rate and is made to perform the same operation. However, sometimes changing the operation of the application according to the link rate is more efficient.
The existing wireless systems include the following systems which control the operation of an application on an STA according to the status of the link.
A first system monitors a received signal strength indication corresponding to an AP in an STA which is a mobile terminal, and boots an application performing communication with the AP when the received signal strength indication is equal to or more than a predetermined value because the distance between the AP and the STA is short and it can be expected that high-speed communication will be realized (patent document 1). Such boot control makes it possible to prevent the STA from moving to the outside of a service area before the completion of communication and prevent the link from being broken as a result of the application being booted when the STA passes through the service area of the AP, and avoid a communication failure.
A second system makes an STA determine whether transmission and reception is possible within a predetermined time according to the status of a link such as a received signal strength indication corresponding to an AP, the amount of information transmitted and received between the STA and the AP and the number of STAs associated with the AP, and boots an application performing communication with the AP (patent document 2).    Patent Document 1: Japanese Unexamined Patent Application Publication No. 2003-235075    Patent Document 2: Japanese Unexamined Patent Application Publication No. 2005-057464